University of Maine, Orono, ME 04469, USA.
Mycologia. 2012 Jan-Feb;104(1):276-94. doi: 10.3852/11-193. Epub 2011 Sep 13.
During the past 5 y the Rhizophydiales, Cladochytriales and Lobulomycetales have been segregated from the formerly recognized Chytridiales. Descriptions of new chytridiomycete orders are based on molecular and ultrastructural characters, which have been phylogenetically mutually supportive. The Polychytrium clade has consisted of a few chitinophilic, soil and aquatic chytrids that clustered in phylogenetic hypotheses but have not been placed in a new order. We isolated additional putative members of this clade, sequenced their nucSSU and nucLSU rDNA and examined zoospores of some of the isolates with TEM. Our isolates are in a well supported clade with previous Polychytrium clade members, but zoospore ultrastructural types vary within the clade, with characters that often are conserved within other orders (e.g. flagellar plug, rumposome) being either present or absent. Based on the isolates in culture we describe the Polychytrium clade as the Polychytriales. This order contains Polychytrium, Lacustromyces, Karlingiomyces, two new genera (Arkaya and Neokarlingia) and additional undescribed taxa.
在过去的 5 年中，根肿菌目、泡囊虫目和毛壶菌目已从以前公认的壶菌目中分离出来。新的壶菌目描述是基于分子和超微结构特征，这些特征在系统发育上是相互支持的。Polychytrium 类群由一些几丁质亲和性、土壤和水生壶菌组成，它们在系统发育假说中聚集在一起，但尚未被置于一个新目。我们分离了这个类群的其他假定成员，对它们的 nucSSU 和 nucLSU rDNA 进行了测序，并使用 TEM 检查了一些分离物的游动孢子。我们的分离物与以前的 Polychytrium 类群成员在一个支持良好的分支中，但游动孢子的超微结构类型在类群内有所不同，某些特征在其他目中经常保守（例如鞭毛塞、rumposome），而在其他目中则存在或不存在。基于培养物中的分离物，我们将 Polychytrium 类群描述为 Polychytriales。这个目包含了 Polychytrium、Lacustromyces、Karlingiomyces、两个新属（Arkaya 和 Neokarlingia）和其他未描述的分类群。
